A. d. Forget the drinks. They'd just add carbon and feed the soil microbes, multiplying their numbers and stealing nutrients, says William D. Bowman, environmental, population and organismic biologist at the University of Colorado.

Urine, on the other hand, will stimulate microbial activity that frees up nitrogen, often in short supply for plant growth. But don't deliver it straight. It will need to be diluted with water, unless you are very well hydrated.

Q.The ancient fear of being taken for dead and then buried alive has given way today to the nightmare of being kept alive indefinitely in a comatose state. But aren't there still circumstances where modern electrocardiography and electroencephalography erroneously fail to detect life? ­E.A. Poe

A. There are cases of severe exposure to cold or overdose of barbiturates or other drugs in which the usual sure indicators may fail, says Jan Bondeson in A Cabinet of Medical Curiosities. A French medical journal told of three suicide attempts where barbiturate overdoses led to erroneous death diagnoses. In one, the victim had "actually recovered while laid out in his coffin."

A man in Belgium was diagnosed as both heart and brain dead after severe exposure to cold; later he revived after being in a comatose state with a low heart rate.

Newspaper accounts also tell of people waking up on an autopsy table following overdoses of drugs while outdoors in the cold. Bondeson himself once observed a woman in the hospital in a comatose state with extremely low body temperature. An alcoholic, she had celebrated New Year's Eve with bottles of vodka while out on her balcony in freezing cold, and fell asleep.

"She was well nigh dead when brought in, her body temperature far below that considered, at the time, consistent with human life," he says. The policemen who brought her in considered her dead. Yet the electrocardiogram did reveal a heart rate, and gradual warming of her blood via a heart-lung machine saved her life. Her marked obesity, isolating her inner organs, probably saved her.

"When I told her she had cheated the Grim Reaper, hoping to wean her from the bottle and save her, she declared that she had indeed learned a lesson– 'Never again would she drink heavily– while seated outside in sub-zero temperatures'!"

Q.Life's a Great Cosmic Crap Shoot. Can you recap the astronomical odds we all had to beat in getting here? ­C. Darwin

A. Start with the 10,000,000,001 protons created in the early universe for every 10,000,000,000 antiprotons, says physicist Lawrence M. Krauss in The Physics of Star Trek. If it weren't for this one extra proton per 10 billion, matter and antimatter would have annihilated each other– end of tale. Post-Big Bang, there had to be just enough stuff to allow matter to clump together, but not so much that it would all fall back together from gravity a Big Crunch.

Now hang the stars in place, and give some of them planets, and the star in question (our sun) had to burn at least the 3.5 billion years it took to get life rolling here. Earth needed to be big enough to hold an atmosphere, with a history of sufficient volcanism to produce ample surface water, and with a moon massive enough or close enough to produce tidal pools to harbor life, but not disruptive daily tidal waves.

All of these had to happen, plus countless more. We are a test case. The fact that we exist proves life is possible. Knowing that life can originate here, the likelihood of it occurring elsewhere is vastly increased.